oh decisions help wanted

so i'm cruising down the road in my 79 z28 at a nice 65 mph halfway to get the thing inspected and all of a sudden i feel a grinding feeling and a little bit of lock up so i begin to pull off. once im down to about 5 mph on the side of the road it completely locks and smoke pours from the rearend of the car. i'm sure everyone here can assume what is coming next. i get my 17 year old self out of the car and look disapointedly sp? under the rear end of the car and see smoke coming from the bearing in the front of my differential and assume the worst. luckily (or so i thought) my dad is a rice farmer so we have our fair share of trailers and i call him and get him to come help me load it onto our lowboy but it gets high centered every time so i call my dad's buddy that owns a wrecker service to come get me. he can barely pull it onto his flatbed because of the lock up but we get it home. that was a few days ago and i tore into the axle today after school. apparently there was a big enough oil leak to of lost nearly all fluid so my bearings went out which let the pinion slide inward and it was grinding against part of my axle shaft. although the gears werent ruined by any means i want to replace the gears. (30 yr old car i think it deserves it) my question is...i want to get a better ratio. im interested in 3.90 gears (fuel prices are kickin my shins) should i just go ahead and get 4.10's? i also need new bearings...i priced Strange Engineering bearings does anyone know of any better brands i should use? and while im workin on the axle i want to replace the sway bar and leaf springs. problem is i dont want to lose any height (i want the same size tire if not bigger tires) and the only springs iv found that boost handling drop the car like an inch and a half. should i just leave the leaf springs and get good shocks? any input and criticism is welcome and appreciated! (sorry for the long thread i felt the story would provide some entertainment or inspire some insight)

The type/size of rear end you have will be a factor in the ratios available. You have to find out what size ring gear you have. Is it a posi unit? Also running a 4.10 gear is going to reduce your gas milage even further.

its a 10 bolt 8.5" and no i don't think it's a posi but it has the 3.73 gears and i dont want the gas mileage of a car with 4.10 gears thats why i'm interested in the 3.90 gears i found

The 3.90 wouldn't be much different mpg wise when compared to the 4.10. I'd stick with the gear ratio you have now if you're worried about the mpg.

that sucks to hear haha thanks though...now say i were more worried about performance than mpg...i should just go ahead and get 4.10 right? i would end up happier no?

well it depends.
do you have a tach?

what is your current cruising RPM
do you drag race a lot or just drive on the street.

when you calculate your rear end gear, you do it to put the engine right at the peak HP rpm as it passes through the traps when you are drag racing.

if you are simply driving on the street though, you will gain much more by doing an intake and exhaust work than by modifying your gears.

if you DO drag race, then as long as it doesnt put your engine over the peak HP RPM, then go up a gear.

if you DONT drag, then PERSONALLY, i would go DOWN a gear and do a full intake and exhaust.
then you can do a cam swap or put in 1.6 lifters or something.

but changing your gears in the pursuit of performance on the street isnt worth it.




as an aside, to get the best economy on the highway, set your rear gear so that the engine is at peak TORQUE RPM at cruising speed.

peak torque usually corresponds with the BSFC peak, which means that the engine is making the most HP per unit of gas used.
BSFC stands for brake specific fuel consumption btw






i hope all that helped
its a lot of info, but not that complicated to understand

thanks a bunch...well it's not cruisin yet but to b completely honest...its not gunna see a track...atleast not netime soon...the only racin itll do is goofin around with friends or if i decide to mess with someone at a light for fun. I guess i will stick with the 3.73 gears it has. i just can't really honestly tell myself i NEED to have the gear upgrade. any advice on bearing brands? and what would you suggest for intake and heads? it has an edelbrock rpm intake and a holley carb not sure on the cfm i'll have to check tomorrow (it had it when i bought it) with stock heads. i can't pull the engine until this fall

by intake, i meant ram air or cold air.
i have seen some pretty trick cold air systems on 2nd gen camaros. most of them were home made.

for exhaust, id recommend a 3" exhaust.
you dont need to worry about emissions iirc, so just skip the cat and do a true dual 3" exhaust system.

for heads, you might want to first do the exhaust, then call up different companies and ask them for advice.
nobody knows how a certain head will work than the people who made it.
just be honest with them about the parts that are on it and how it will be used.

if you want to spend big money (1,200 ish) you can get a whole kit that has new heads and a matched cam, with lifters and rockers all in one.
check out summit racing for that.

alrite thanks...how can i route a cold air system to the air filter on the carb? do u have any pics i can see?

not personally, but do a google search.
if you want, ram air hoods are available, as are cowl induction hoods
i guess with a carb, you cant really get too much more sophisticated than a simple tube going from the air cleaner to under the bumper or something like that.



hood scoop
http://images.highperformancepontiac.com/features/0710_hppp_05_z+1968_pontiac_firebird+engine.jpg

my uncle worked up something for his 68 cougar that was simple aluminum tube going from the air cleaner assembly to front of the car, then he put a 90* bend in and routed it to a box he constructed under the bumper.

im sure you can visualize what im talking about

yeah i see what u mean. it already has a cowl hood on it.

can't go wrong with Richmond Gears for the rearend.

since you have a cowl hood already, just stick with an open element.

alrite thanks and sweet camaro and ferrari sounds like uv got the best of both worlds